Far too many weaklings in this world. The weaklings in this case were that pack of bullies. Had they known their own strength, and maybe felt a few of those blows in a monitored training session, they would not be dishing them out. It's a lot harder to hurt someone when you know how bad it feels. Becoming overly aggressive in a training session is disciplined, then they learn their limits. It's also a lot harder to bully someone when they can come back at you with equal force.

Teach kids the real world.